1. The Field of the Invention
The present invention relates generally to medical apparatus and methods. More particularly, the present invention relates to apparatus and methods to permit external control of flow through internal body lumens.
Urinary incontinence is a significant problem for a number of adult men and women throughout the world. Severe cases of urinary incontinence may be treated by implantation of an artificial sphincter which comprises an inflatable cuff placed around the urethra, particularly in men. The cuff may be selectively inflated and deflated through use of a remote pump module which is subcutaneously implanted and manipulated through the skin. Although effective to some extent, such manually inflatable systems have a number of drawbacks. Implantation of the pump is difficult and locations where the pump may be actuated through the skin are limited, particularly in women. Many patients find it difficult to manually actuate the pump through the skin, and subsequent modification and adjustment of the pump system generally requires a repeat operation.
For all these reasons, it would be desirable to provide alternative and/or improved implantable systems for selectively controlling flow through the urethra and other body lumens. Such systems should be relatively easy to implant, should permit straight forward and reliable operation by the patient, should have a long life, and should permit convenient reprogramming and/or system interrogation without the need to surgically access the implanted component(s) of the system. At least some of these objectives will be met by the invention described hereinafter.
2. Description of the Background Art
U.S. Pat. No. 4,556,050, describes an artificial sphincter which is implantable about a body lumen. The sphincter includes a shape memory component which can be opened by applying power through an implanted pick-up coil. U.S. Pat. Nos. 5,556,414; 5,480,431; and 5,466,242, describe stents having shape memory components which can be reconfigured by applying energy.